✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns — Slider direction correct ✓ Full slider range — Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects — Physics correct ✓ Live mass value ✓ Live volume value ✓ Live density value ✓ Live displaced water ✓ Gilded displaces more ✓ Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Slider direction is inverted (transform:rotate(180deg) with writing-mode bt-lr causes top=water, bottom=air), crowns have no fall animation (they teleport via transform), and the submerged-ratio/water-rise physics uses arbitrary pixel scaling rather than genuine Archimedes proportionality, though displaced-volume values and the gilded-displaces-more relationship are directionally correct.
Slider direction is inverted (transform:rotate(180deg) with writing-mode bt-lr causes top=water, bottom=air), crowns have no fall animation (they teleport via transform), and the submerged-ratio/water-rise physics uses arbitrary pixel scaling rather than genuine Archimedes proportionality, though displaced-volume values and the gilded-displaces-more relationship are directionally correct.